WO2023240370A1

WO2023240370A1 - Injection mould with multi-part mould insert frame

Info

Publication number: WO2023240370A1
Application number: PCT/CH2023/050017
Authority: WO
Inventors: Rolf MÜHLEMANN
Original assignee: Fostag Formenbau Ag
Priority date: 2022-06-17
Filing date: 2023-05-23
Publication date: 2023-12-21
Also published as: CH719787A1

Abstract

In an injection mould comprising a mould insert frame (3) for receiving a multiple-nozzle head (4) and a plurality of mould inserts (7) each having a cavity formed therein, each of which can be supplied with plastic melt via the multiple-nozzle head (4); wherein the mould insert frame (3) has a central aperture (4), which extends in an axial direction (A) and in which the multiple-nozzle head (3) is received, and a plurality of peripheral apertures (5), which are arranged around the central aperture (4) and extend in the axial direction (A) and in each of which one of the plurality of mould inserts (7) is received; there is provision that the mould insert frame (3) comprises a central frame part (31, 31') with the central aperture (4) and at least one peripheral fixing part (32, 32') which can be removed from the central frame part (31, 31'); wherein the plurality of peripheral apertures (5) are formed by the central frame part (31, 31') and the at least one peripheral fixing part (32, 32'); wherein a separation (T) between the central frame part (31, 31') and the at least one removable peripheral fixing part (32, 32') runs through the respective peripheral aperture (5) in such a way that, with a peripheral fixing part (32, 32') removed, the mould insert (7) can be taken out from the central frame part (31, 31') from the multiple-nozzle head (3) in a direction (R) perpendicular to the axial direction (A).

Description

Injection molding tool with multi-part mold insert frame

Technical area

The invention relates to an injection molding tool with a mold insert frame for receiving and mounting a multiple nozzle head and a plurality of mold inserts arranged around the multiple nozzle head.

Technical background

Injection molding tools with multiple mold inserts, which are supplied with a plastic melt via a multiple nozzle head, usually have a mold insert frame in which the multiple nozzle head and the multiple mold inserts are accommodated and mounted. For this purpose, the mold insert frame has a central recess for the multiple nozzle head, which extends in a vertical direction, and a plurality of peripheral recesses for the mold inserts, which are arranged evenly around the central recess and also extend in the axial direction. The axial direction is also the closing or Opening direction of the injection molding tool.

The multiple nozzle head comprises a primary melt channel, which branches at one end of the multiple nozzle head into a plurality of secondary melt channels, which run essentially perpendicular to the axial direction and open laterally into the mold insert. The secondary melt channel is connected at a proximal end to the primary melt channel and at a distal end to an antechamber through a nozzle tip attached to the nozzle head. The antechamber is formed partly by the multiple nozzle head and partly by the respective mold insert, which are sealingly connected to one another. The nozzle tip usually extends into a corresponding recess in the mold insert. Accordingly, the mold inserts can be positioned and fixed very precisely compared to the multiple nozzle head using the respective recesses.

During normal operation of the injection molding tool, it may happen that individual mold inserts need to be maintained and cleaned. In order to remove the mold insert to be cleaned, the corresponding mold insert, together with the multiple nozzle head and all other mold inserts, must be removed from the injection molding tool in the axial direction. the recesses in the mold insert frame. The faulty mold insert can then be removed from the multiple nozzle head in a direction perpendicular to the axial direction can be removed. Assembling and reinserting the mold inserts and the multiple nozzle head into the injection molding tool is extremely time-consuming and requires a great deal of skill because all mold inserts must be precisely aligned with the multiple nozzle head before all elements are inserted together into the corresponding recesses in the insert frame can. There is also a high risk of damaging the nozzle tips or other parts.

In order to enable easier installation and removal of a mold insert, WO20227817A1 suggests designing the nozzle tip to be detachable in the axial direction. The mold insert can be removed in the axial direction together with the nozzle tip. However, if there is still solid plastic in the nozzle and especially in the nozzle tip and the corresponding antechamber, cold removal of the mold insert is hardly possible. Another problem is the seal between the nozzle tip and the multiple nozzle head. Even a very slight play in the nozzle tip inevitably leads to leaks. In addition, instead of a conventional multiple nozzle head available on the market, a specially suitable multiple nozzle head with a nozzle tip that can be removed in the axial direction must be used.

EP0743157 and WO09124865 each describe systems with individually removable nozzle tips in order to then remove the mold insert. In EP0743157, an upper part of the mold insert must also be removed beforehand, which can result in further leaks. Even with these systems, cold removal of a mold insert is hardly possible if there are solid plastic residues.

Presentation of the invention

One object of the invention is to provide an injection molding tool which does not have the disadvantages mentioned above. This task is solved by an injection molding tool with the features of claim 1.

The injection molding tool comprises a mold insert frame for receiving a multiple nozzle head and several mold inserts, each with a cavity formed therein, which can each be supplied with plastic melt via the multiple nozzle head. The mold insert frame has a central recess extending in an axial direction, in which the multiple nozzle head is received, and a plurality of peripheral ones arranged around the central recess and extending in the axial direction Recesses, in which one of the several mold inserts is accommodated. The mold insert frame comprises a central frame part with the central recess and at least one peripheral fixing part which can be removed from the central frame part, the plurality of peripheral recesses being formed by the central frame part and the at least one peripheral fixing part. A separation between the central frame part and the at least one removable peripheral fixing part runs through the plurality of peripheral recesses in such a way that when the peripheral fixing part is removed, the mold insert can be removed from the central frame part in a direction perpendicular to the axial direction of the multiple nozzle head.

Such a multi-part mold insert frame, which can be accommodated in a tool plate of the injection molding tool, allows a mold insert to be easily removed from the corresponding nozzle tip of the multiple nozzle head in a radial direction. This enables cold expansion. In addition, the central frame part ensures that the remaining mold inserts that have not been removed are held on the multiple nozzle head in the correct position. For later reinstallation, no laborious alignment of the individual mold inserts with the respective peripheral recesses is necessary, as is the case with conventional one-piece mold insert frames. The system can also be combined with conventional multiple nozzle heads without complex, removable nozzle tips.

Preferred embodiments of the invention are set out in the dependent claims.

In some embodiments, the central frame part can form an inner, proximal (ie closer to the center or the central recess) circumferential surface of the plurality of peripheral recesses and the at least one peripheral fixing part can form an outer, distal (ie further away from the center or the central Recess) form the peripheral surface of the several peripheral recesses. The two peripheral surfaces form the peripheral recess in which the mold insert is positioned and fixed exactly opposite the nozzle tip. Already the part of the recess in the central frame part and its proximal peripheral surface are designed in such a way that the mold insert can be precisely positioned and held therein. As a rule, the proximal circumferential surface on the central frame part spans a maximum of 180 degrees of the peripheral recess so that the mold unit can be removed in a (radial) direction perpendicular to the axial direction. In some embodiments, the peripheral fixing part can be formed by a tool plate of the injection molding tool, into which the central frame part can be inserted together with the multiple nozzle head and the multiple mold inserts. During removal, the central frame part together with the multiple nozzle head and the mold inserts are removed from the tool plate in the axial direction using a suitable tool. lifted from the peripheral fixing part. The mold insert can then be removed from the nozzle tip in a direction vertical to the axial direction from the central frame part.

In some embodiments, the mold insert frame can comprise a single peripheral fixing part surrounding the central frame part, which can be inserted into a tool plate of the injection molding tool together with the central frame part, the multiple nozzle head and the several mold inserts. When removing the mold insert frame, the mold insert frame is first pulled out of the tool plate in the axial direction using a suitable tool. The central frame part together with the multiple nozzle head and the mold inserts are then pulled out of the peripheral fixing part in the axial direction using a suitable tool. Then the mold insert can be removed from the central frame part from the nozzle tip in a direction vertical to the axial direction.

In some embodiments, the mold insert frame may comprise a plurality of peripheral fixing parts which can be inserted into a tool plate of the injection molding tool together with the central frame part, the multiple nozzle head and the plurality of mold inserts. The plurality of peripheral fixing parts can be arranged in corresponding recesses in the central frame part. The plurality of peripheral fixing parts can be individually removable from the central frame part in a direction perpendicular to the axial direction. When removing the mold insert frame, the mold insert frame is first pulled out of the tool plate in the axial direction using a suitable tool. One of the several peripheral fixing parts can then be removed from the central frame part. Then the mold insert can be removed from the central frame part from the nozzle tip in a direction vertical to the axial direction.

In some embodiments, the plurality of peripheral recesses may be circular with one or more circular cylindrical sections.

In some embodiments, an outer contour of the mold insert frame is cylindrical, preferably with several circular cylindrical sections. The mold insert frame can be accommodated in a corresponding recess in the tool plate. In some embodiments, the peripheral recess can have a circumferential shoulder against which the mold insert rests when installed and on which the mold insert is guided during installation or removal. The mold insert can have a correspondingly complementary shoulder.

In some embodiments, the central frame part can each have a recess between the central recess and the plurality of peripheral recesses, in which a respective nozzle tip of the multiple nozzle head is arranged.

In some embodiments, the peripheral recesses may be arranged evenly distributed around the central recess. As a rule, they are arranged in a circle. The mold insert frame can have 2 to 8 recesses and correspondingly 2 to 8 mold inserts, each of which is connected to a central multiple nozzle head.

In some embodiments, the separation may be substantially circular and each divide the peripheral recesses into approximately two equal parts. This is particularly advantageous in the case of a substantially annular peripheral fixing part.

In some embodiments, the central frame part can have a plurality of elongated, radially outwardly open recesses with essentially parallel side walls, into which one of the plurality of peripheral fixing parts can be inserted and thereby forms the peripheral recess. The separation between the central frame part and the peripheral fixing part runs along the essentially parallel side walls of the recess.

In some embodiments, the plurality of mold inserts can be held in position in the peripheral recesses of the central frame part even when the peripheral fixing part is removed.

In some embodiments, the multiple nozzle head can have a primary melt channel, which can run in the axial direction, and for each cavity have a secondary melt channel branching off from the primary melt channel, which can run in the radial direction. The secondary melt channel can be connected at a proximal end to the primary melt channel and at a distal end to a cavity through a nozzle tip attached to the nozzle head.

In some embodiments, the multiple nozzle head may have multiple nozzle tips for laterally spraying the multiple cavities. In some embodiments, the injection molding tool can have a cover plate with which the mold inserts and/or the multiple nozzle head are fixed in the respective recesses.

In some embodiments, the plurality of mold inserts can have a fastening means for a suitable tool on the side opposite the respective nozzle tip, so that the plurality of mold inserts can be pulled out of the central frame part with the suitable tool in a direction perpendicular to the axial direction. The fastening means can, for example, be a hole with an internal thread into which a suitable tool can be screwed. The fastening means can also have one or more openings into which a suitable tool can engage and clamp.

The injection molding tool can also have several mold insert frames described above with multiple nozzle heads and several mold inserts.

Short explanation of the characters

The invention will be explained in more detail below using exemplary embodiments in connection with the drawing(s). Show it:

Fig. 1 is a perspective view of an injection molding tool with a two-part mold insert frame;

Fig. 2 is a perspective view of the injection molding tool from Fig. 1 with the mold insert frame removed;

Fig. 3 is a top view of the two-part mold insert frame from Fig. 1;

Fig. 4 is a perspective view of the two-part mold insert frame from Fig. 1 with the central frame part removed;

Fig. 5 is a perspective view of the central frame part from Fig. 1 with the mold insert removed;

Fig. 6 is an exploded perspective view of the mold insert frame from Fig. 1 with multiple nozzle head and a mold insert;

Fig. 7 is a perspective view of an injection molding tool with the multi-part mold insert frame removed;

Fig. 8 is a top view of the multi-part mold insert frame from Fig. 7; 9 is a perspective view of the multi-part mold insert frame from FIG. 7 with the peripheral fixing part removed;

10 is a perspective view of the multi-part mold insert frame from FIG. 7 with the mold insert removed;

Fig. 11 is a perspective view of the central frame part from Fig. 7 with the multiple nozzle head removed.

Ways of carrying out the invention

Fig. 1 shows an injection molding tool or a tool plate 1 of an injection molding tool with several mold inserts 7. In the embodiment shown, the mold inserts 7 are arranged in a circle around a multiple nozzle head 6, which supplies a cavity of the respective mold insert 7 with plastic melt. An antechamber for the plastic melt is formed by a recess in the mold insert 7, into which a nozzle tip 61 of the multiple nozzle head 6 projects.

The multiple nozzle head 6 and the multiple mold inserts 7 must therefore be arranged in a sealing manner to one another in the area of the antechamber. This is usually achieved by holding the multiple nozzle head 6 and the multiple mold inserts 7 in a mold insert frame 3 and in this way fixing them in the correct position relative to each other. For this purpose, the mold insert frame 3 has a central recess 4 for the multiple nozzle head 6 and several peripheral recesses 5 for the several mold inserts 7. These recesses 4, 5 and their arrangement can be clearly seen in FIG. 3, among others. Fig. 3 shows a top view of the two-part mold insert frame 3 from Fig. 1.

The mold insert frame 3, the multiple nozzle head 6 and the mold inserts 7, which are installed in a tool plate, for example in a receptacle 11 for the mold insert frame 3, can further be provided and fastened with a cover plate 2.

In the embodiment of FIG. 1, a two-part mold insert frame 3 is shown. This has a central frame part 31 and an annular peripheral fixing part 32. The central recess 4 is formed in the center of the central frame part 32 (see FIG. 3). The plurality of peripheral recesses 5 are arranged in a circle around the central recess 5 and are formed by both an outer contour of the central frame part 31 and an inner contour of the peripheral fixing part 32 (see FIG. 3), so that a separation T between the two frame parts 31 , 32 through the peripheral recesses 5 runs. The central frame part 31 forms a proximal peripheral surface 51 of the peripheral recess 5, which spans a maximum of 180 degrees of the peripheral recess 5. The peripheral fixing part 32 forms a distal circumferential surface 52 of the peripheral recess 5, which spans a maximum of 180 degrees of the peripheral recess 5. These peripheral surfaces 51, 52 can be clearly seen in FIGS. 3 to 6.

2 shows a situation in which the mold insert frame 3 comprising the inner and peripheral fixing part 31, 32 is removed together with the multiple nozzle head 6 accommodated therein and the multiple mold inserts 7. For this purpose, the mold insert frame 3 is lifted out of the receptacle 11 of the tool plate in the axial direction A using a suitable tool.

In Fig. 4, the mold insert frame 3 is shown in a situation in which the central frame part 31 is removed together with the multiple nozzle head 6 accommodated therein and the multiple mold inserts 7. For this purpose, the central frame part 31 with the several mold inserts 7 is lifted out of the outer annular frame part 32 in the axial direction A using a suitable tool. The peripheral recesses are generally designed in the shape of a circular cylinder, with sections being able to have different diameters so that a circumferential shoulder 53 is formed. The mold insert 7, which is also circular-cylindrical in shape, has a complementary shoulder 72, with which it can rest on the circumferential shoulder 53 of the peripheral recess 5 in the installed state and can be guided during installation and removal.

Fig. 5 shows the central frame part 31 with the multiple nozzle head 6 and the several mold inserts 7. Two of the several mold inserts are removed by being pulled out of the corresponding peripheral recess 5 in the radial direction R, i.e. perpendicular to the axial direction A. In Fig. 5 a nozzle tip 61 of the multiple nozzle head 6 and an antechamber 71 of a mold insert 7 can be seen. The design of the central frame part 31 and the peripheral recesses 5 allows the mold insert 7 to be removed from the nozzle tip 61 without having to remove it. The excellent nozzle tip 71 is accommodated in a recess 54 of the central frame part 31, which forms a breakthrough between the central recess 4 and the respective peripheral recesses 5.

Finally, Fig. 6 shows the mold insert frame 3 in Fig. 1 with the multiple nozzle head

6 and a mold insert 7 in an exploded view.

In contrast to the embodiment from FIG. 1, Fig. 7 shows an embodiment of the injection molding tool with a removed multi-part mold insert frame 3, which has a central frame part 3T and several peripheral fixing parts 32 '. Each peripheral fixing part 32 'holds one of the plurality of mold inserts 7 in the corresponding peripheral recess 7, which are also arranged around the central recess 4. These recesses 4, 5 and their arrangement can be clearly seen in FIG. 8, among others. Fig. 8 shows a top view of the multi-part mold insert frame 3 from Fig. 7.

The central frame part 3T has a plurality of elongated, radially outwardly open recesses 33 'with essentially parallel side walls 34' (cf. Fig. 10), into which one of the plurality of peripheral fixing parts 32' can be inserted and one of the plurality of peripheral recesses 5 trains.

1, the peripheral recess 5 is formed by the central frame part 3T and the peripheral fixing part 32' and also has a proximal circumferential surface 51 formed by the central frame part 3T and a distal circumferential surface 52 formed by the peripheral fixing part 32' on.

1, when a mold insert 7 is removed, the inner frame part is not lifted axially out of the peripheral fixing part, but a peripheral fixing part 3T is lifted out of the recess 33 'of the central frame part 3T in the radial direction R perpendicular to the axial direction A removed. This releases the mold insert 7 and can also be removed in the radial direction R. Fig. 9 shows a multi-part mold insert frame 3 with the peripheral fixing part 32 'removed. Fig. 10 shows a multi-part mold insert frame 3 with the mold insert 7 removed.

Finally, Fig. 11 shows an empty central frame part 3T with the multiple nozzle head 6 removed.

Label list

1 tool plate

11 Holder for mold insert frame

2 cover plate

3 mold insert frames

31, 3T central frame part

32, 32' peripheral fixing part

33' recess

34' sidewall 4 central recess

5 peripheral recess

51 proximal circumferential surface

52 distal circumferential surface 53 shoulder

54 recess

6 multiple nozzle heads

61 nozzle tip

7 mold insert 71 antechamber

72 shoulder

A axial direction

R radial direction T separation

Claims

Patent claims

1 . Injection molding tool comprising a mold insert frame (3) for receiving a multiple nozzle head (6) and a plurality of mold inserts (7), each with a cavity formed therein, which can each be supplied with plastic melt via the multiple nozzle head (6); wherein the mold insert frame (3) has a central recess (4) extending in an axial direction (A), in which the multiple nozzle head (6) is received, and several arranged around the central recess (4) and extending in the axial direction (A) has extending, peripheral recesses (5), in each of which one of the plurality of mold inserts (7) is received; characterized in that the mold insert frame (3) comprises a central frame part (31, 3T) with the central recess (4) and at least one peripheral fixing part (32, 32 ') removable from the central frame part (31, 3T); wherein the plurality of peripheral recesses (5) are formed by the central frame part (31, 3T) and the at least one peripheral fixing part (32, 32'); wherein a separation (T) between the central frame part (31, 3T) and the at least one removable peripheral fixing part (32, 32') runs through the respective peripheral recess (5) in such a way that when the peripheral fixing part (32, 32') is removed ) the mold insert (7) can be removed from the central frame part (31, 3T) in a direction (R) perpendicular to the axial direction (A) of the multiple nozzle head (3).

2. Injection molding tool according to claim 1, characterized in that the central frame part (31, 3T) forms an inner, proximal peripheral surface (51, 5T) of the plurality of peripheral recesses (5) and the at least one peripheral fixing part (32, 32 '). outer, distal peripheral surface (52, 52 ') of the plurality of peripheral recesses (5).

3. Injection molding tool according to one of the preceding claims, characterized in that the peripheral fixing part is formed by a tool plate of the injection molding tool, into which the central frame part (31, 3T) can be used together with the multiple nozzle head (6) and the multiple mold inserts (7).

4. Injection molding tool according to one of claims 1 to 2, characterized in that the mold insert frame (3) comprises a single peripheral fixing part (32) surrounding the central frame part (31), which together with the central frame part (31), the multiple nozzle head (6) and the several mold inserts (7) can be inserted into a tool plate (1) of the injection molding tool.

5. Injection molding tool according to one of claims 1 to 2, characterized in that the mold insert frame (3) comprises a plurality of peripheral fixing parts (32 '), which together with the central frame part (3T), the multiple nozzle head (6) and the plurality of mold inserts (7) can be inserted into a tool plate (1) of the injection molding tool.

6. Injection molding tool according to claim 5, characterized in that the plurality of peripheral fixing parts (32 ') can be individually removed from the central frame part (3T) in a direction (R) perpendicular to the axial direction (A).

7. Injection molding tool according to one of the preceding claims, characterized in that the plurality of peripheral recesses (5) are circular with one or more circular cylindrical sections.

8. Injection molding tool according to one of the preceding claims, characterized in that the peripheral recess (5) has a circumferential shoulder (53) against which the mold insert (7) rests when installed and on which the mold insert (7) lies during installation or removal is guided.

9. Injection molding tool according to one of the preceding claims, characterized in that the central frame part (31, 3T) between the central recess (4) and the plurality of peripheral recesses (5) each has a recess (54), in each of which a nozzle tip ( 61) of the multiple nozzle head (6) is arranged.

10. Injection molding tool according to one of the preceding claims, characterized in that the peripheral recesses (5) are arranged evenly distributed around the central recess (4). Injection molding tool according to one of the preceding claims, characterized in that the separation (T) is essentially circular and divides the peripheral recesses (5) into approximately two equal parts. Injection molding tool according to one of claims 5 to 10, characterized in that the central frame part (3T) has a plurality of elongated, radially outwardly open recesses (33 ') with essentially parallel side walls (34'), into which one of the plurality of peripheral fixing parts can be inserted (32 ') can be used and thereby forms one of the several peripheral recesses (5). Injection molding tool according to one of the preceding claims, characterized in that the plurality of mold inserts (7) are held in position in the peripheral recesses (5) of the central frame part (31, 3T) even when the peripheral fixing part (32, 32 ') is removed. Injection molding tool according to one of the preceding claims, characterized in that the multiple nozzle head (6) has a plurality of nozzle tips (61) for lateral injection into the plurality of cavities. Injection molding tool according to one of the preceding claims, characterized in that the plurality of mold inserts (7) each have a fastening means for a suitable tool on the side opposite the respective nozzle tip (61), so that the plurality of mold inserts (7) with the suitable tool in the direction (R) can be pulled out of the central frame part (3T) perpendicular to the axial direction (A).